Hello John,
You should have what is known as a clam type foot control, on the older type foot controls there was a rubber cover covering the complete bottom of the control, you need to peel the rubber back, it may well crack because of age so be careful, when you peel the rubber back you will see a screw in the centre, undo the screw all the way, once again the middle of the screw may break away with the plastic but it can be glued back together again, once it is undone you can open the control.
ken
drivewithken, April 2009
